Timing system and device and method for making the same

ABSTRACT

A timing device for indicating the passage of a duration of time is disclosed. The timing device and system, in accordance with the embodiments of the invention, comprise an electrochemical component which generates a visual and/or audio indication of the passage of time. The timing device further comprises a compensating element, such as a varistor, a thermistor and/or combinations thereof. The compensating element regulates the response of the device with respect to changes in temperature. The timing device is configured to indicate the passage of a single duration of time or comprises zones that are activated in a range of prescribed times and individually or collectively indicate the passage of time or the passage of a range of times.

RELATED APPLICATION(S)

This Patent Application is a continuation of U.S. patent applicationSer. No. 14/025,398 filed on Sep. 12, 2013 and entitled “TIMING SYSTEMAND DEVICE AND METHOD FOR MAKING THE SAME,” which is a continuation ofU.S. patent application Ser. No. 13/185,260, filed on Jul. 18, 2011, andentitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THE SAME,” nowissued as U.S. Pat. No. 8,559,278 which is a continuation of U.S. patentapplication Ser. No. 12/315,524, filed on Dec. 3, 2008, and entitled“TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THE SAME,” which is acontinuation of U.S. patent application Ser. No. 11/888,226, filed onJul. 30, 2007, and entitled “TIMING SYSTEM AND DEVICE AND METHOD FORMAKING THE SAME,” now issued as U.S. Pat. No. 7,463,558 which is adivisional of U.S. patent application Ser. No. 10/840,880, filed on May7, 2004, and entitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKINGTHE SAME,” now issued as U.S. Pat. No. 7,254,095 which is acontinuation-in-part of the U.S. patent application Ser. No. 10/376,672filed Feb. 26, 2003 and entitled “TIMING SYSTEM AND DEVICE AND METHODFOR MAKING THE SAME,” now issued as U.S. Pat. No. 6,822,931 which is acontinuation-in-part of the U.S. patent application Ser. No. 10/319,233filed Dec. 13, 2002, and entitled “TIMING SYSTEM AND DEVICE AND METHODFOR MAKING THE SAME,” now issued as U.S. Pat. No. 6,801,477. This PatentApplication also claims priority under 35 U.S.C. 119 (e) of the U.S.Provisional Patent Application, Ser. No. 60/469,467, filed May 8, 2003,and entitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THE SAME”.The U.S. patent application Ser. No. 10/376,672 filed Feb. 26, 2003 andentitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THE SAME,” theU.S. patent application Ser. No. 10/319,233 filed Dec. 13, 2002, andentitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THE SAME, theProvisional Patent Application, Ser. No. 60/469,467, filed May 8, 2003,and entitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THE SAME,”the U.S. patent application Ser. No. 10/840,880, filed on May 7, 2004,and entitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THE SAME,”and the U.S. patent application Ser. No. 11/888,226, filed on Jul. 30,2007, and entitled “TIMING SYSTEM AND DEVICE AND METHOD FOR MAKING THESAME” are also hereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates to timing systems and devices and a method formaking the same. More specifically, the invention relates to systems anddevices for and methods of indicating the passage of a duration of time.

BACKGROUND OF THE INVENTION

There are a number of different timing systems and devices, generallyreferred to as time-temperature indicators (TTIs), which can be used tomonitor the exposure of objects to a range of temperatures over aspecified period of time. In an early example, Witonsky, in U.S. Pat.No. 3,942,467, describes a time-temperature indicator with anencapsulated inner container and a pH sensitive dye solution containedtherein. The device of Witonsky further has an encapsulated outercontainer containing an organic material which undergoes solvolysis. Theouter container and the inner container are separated by a membrane.When the membrane between the inner container and the outer container isbroken, the contents of the containers mix and over a period of timechange color, thus providing an indication of the passage of a durationof time. A number of other time-temperature indicators utilize wickingtechniques (such as described in U.S. Pat. No. 5,709,472 and U.S. Pat.No. 6,042,264, both issued to Prusik et al.) or diffusion layertechniques (such as described in U.S. Pat. No. 4,629,330 issued toNichols and U.S. Pat. Nos. 5,930,206 and 5,633,835 both issued to Haaset al.). In U.S. Pat. No. 6,198,701 issued to De Jonghe et al., anelectrochemical timing device is described, whereby consumption of anelectrode is used to provide an indication of the passage of a durationof time.

Time-temperature indicators can have a number of different applicationsfor indicating when an event or activity needs to take place. Forexample, time-temperature indicators have applications for indicatingwhen perishable materials have expired and need to be thrown out.Time-temperature indicators also have applications for general inventorymanagement, for monitoring projects, activities and a host of other timeand/or temperature dependent events. Therefore, there is a continuedneed to develop reliable timing systems and devices which can be usedfor a variety of different applications.

SUMMARY OF THE INVENTION

The present invention is directed to a device and system for indicatingthe passage of a duration of time and a method of making the same. Whilethe present invention is referred to herein as a timing device, it isunderstood that the timing device of the present invention can also besensitive to temperature. While a timing device, in accordance with theembodiments of the invention, can be configured to be more or lesssensitive to temperature, the timing device will generally react, orchange, at a faster rate at higher temperatures unless the timing deviceis configured with a temperature compensating element, such as describedin detail below.

A timing device, in accordance with the embodiments of the presentinvention, is a chemical-based timing device, electrochemical-basedtiming device, or a combination thereof. The timing device, whenactuated, provides a visual indication of a passage of time. The timingdevice is configured as a “stand alone” indicator or, alternatively, isconfigured to be coupled with any number of circuits which also providean audible signal or otherwise sense and/or store information regardingthe operation of the device.

The device preferably comprises a lens, a base and means for alteringthe visibility of the base through the lens and thereby indicating thepassage of a duration of time. The means for altering the visibility ofthe base through the lens preferably comprises an optical mediumpositioned between the lens and the base. The optical medium compriseschemicals and/or elements of a battery that react or otherwise changeover time and, thereby alters the visibility of the base through thelens. For example, one or more of the materials, layers or components ofthe optical medium are converted from opaque to transparent or,alternatively, from transparent to opaque, thereby increasing ordecreasing the visibility of the base through the lens, respectively.Alternatively, one or more of the materials, layers or components of theoptical medium are dissolved or depleted, thereby altering thevisibility of the base through the lens.

In accordance with the embodiments of the invention, the optical mediumcomprises a solid layer positioned between the lens and the base, and afluid layer positioned between the solid layer and the base. Because thesolid layer is preferably plated or coated directly onto the lens, thesolid layer is also referred to herein as a lens coating layer. Thefluid layer contains gel, water and any suitable chemical(s) required tochange the solid layer from opaque to transparent, change the solidlayer from transparent to opaque, deplete the solid layer, or dissolvethe solid layer, as explained in detail below. In the preferredembodiment of the invention, the solid layer is opaque and when thedevice is actuated, the fluid layer dissolves the solid layer over aduration of time, thereby making the base visible through the lens andindicating the passage of a duration of time.

In further embodiments of the invention, a timing device comprises anindicator between the lens and the lens coating layer to enhance thevisual indication of the passage of time. Suitable indicators are fluidsor solids, and can include, but are not limited to, pH indicators andreactive dye indicators, which generate a color change when reacted withthe fluid layer, after the fluid layer sufficiently depletes ordissolves the lens coating layer. Alternatively, the lens coating layeris a semi-porous membrane layer, wherein the indicator provides a colorchange when a sufficient amount of the reactive species from the fluidmedium migrates through the membrane layer.

In still further embodiments of the invention, a timing device comprisesa battery, wherein at least a portion of the optical medium between thesolid layer and the base actively participates in an electrochemicalprocess resulting in a visual change indicating the passage of aduration of time. In accordance with this embodiment of the invention,the battery is a galvanic cell and the optical medium comprises anelectrolyte. A galvanic cell is a battery in which reduction andoxidation of species within the battery will occur spontaneously as longas there is a conductive path from a first electrode of the cell to asecond electrode of the cell. In operation a material within theelectrolyte is plated between the base and the lens, thereby reducingthe visibility of the base through the lens. Alternatively, an opaqueelectrode positioned between the lens and the base is depleted, therebyincreasing the visibility of the base through the lens.

In still further embodiments of the invention, the battery is anelectrolytic cell. An electrolytic cell requires a current from anotherbattery, or other current source, to drive the reduction and oxidationof species within the battery. In accordance with this embodiment, acurrent from an external battery, or current source, flows through thebattery and a material within the electrolyte is plated out between thelens and the base, thereby reducing the visibility of the base throughthe lens. Alternatively, an opaque electrode positioned between the lensand the base is depleted, thereby increasing the visibility of the basethrough the lens.

Regardless of whether a timing device is configured to operate as agalvanic cell or as an electrolytic cell, the timing device can comprisea colored electrolyte. In accordance with the embodiments of theinvention, the colored electrolyte becomes visible after depleting oneor more electrode materials positioned between a transparent lens andthe colored electrolyte, thereby indicating the passage of a duration oftime. For example, a timing device comprises a clear lens formed from apolymer, such as polyester. The polyester lens is coated with a firstelectrode material, such as aluminum. The timing device furthercomprises a base structure with a second electrode material. The secondelectrode material can be any metal with a reduction potential that isdifferent from a reduction potential of the first electrode material. Ifthe device is being operated as an electrolytic cell, as explainedabove, then the reduction potential of the first electrode material andthat of second electrode material can be the same. Between the firstelectrode material and the base structure is the colored electrolyte,and when the device is activated the first electrode material isdepleted from the transparent lens and the colored electrolyte becomesvisible, thereby indicating the passage of the duration of time.

In yet further embodiments of the invention, a timing device isconfigured to operate as a galvanic cell or as an electrolytic cell andcomprises a modified electrolyte. In accordance with this embodiment,the modified electrolyte includes a compensating material to controlresistance to ion transport or migration through the modifiedelectrolyte as a function temperature. For example, magnesium dioxidepowder or granules are mixed with an ionic aqueous or gel electrolytesolution to provide a temperature dependent resistance to ion transportor migration through the ionic aqueous or gel electrolyte solution.

In accordance with further embodiments of the invention, a timing deviceis configured with a lens structure and/or the base structure formedfrom a conductive polymer with an electrode material coated thereon. Theconductive polymer is believed to help ensure uniform plating and/ordepletion of electrode materials when the device is activated, such asdescribed in detail above. Alternatively, or in addition to the use of aconductive polymer, as described above, a metal screen can be in contactwith, or imbedded in, one or more of the electrode materials to helpensure uniform plating and/or depletion of electrode materials.

In still further embodiments of the invention, a timing device isconfigured to operate as an electrochemical cell and includes anelectrolyte with an indicator. For example, the timing device comprisesan electrolyte with a pH indicator that changes color when theelectrochemical cell is activated, such as described above, and theelectrochemical cell generates a sufficient concentration of an ion or apH altering species within the electrolyte.

A timing device, in accordance with the embodiments of the invention, isactuated using any number of different mechanisms or combination ofmechanisms. For example, if the timing device is a chemical-based timingdevice, the timing device is preferably formed in parts, wherein a firstpart comprises a first reactive region and a second part comprises asecond reactive region. To form an activated device, the first part andthe second part are brought together and the first reactive region andthe second reactive region are held in an eclipsed or overlappingposition and in contact. Alternatively, a chemical-based timing devicecomprises a membrane or a removable structure separating the reactiveregions of the device, wherein the membrane is broken or the structureis removed to activate the device.

In accordance with the embodiments of the invention, a timing device isan electrochemical-based timing device with electrodes that are inelectrical communication with each other. The timing device furtherincludes one or more electrolyte solutions that are positioned betweenthe electrodes and that are separated by a membrane. The membrane can beformed from plastic, glass or any other material or combination ofmaterials that are capable of preventing or reducing the migration ofions through the electrolyte and, thus, prevent or reduce the flow ofcurrent between the electrodes. To actuate the timing device, themembrane is ruptured or broken allowing the migration of ions throughthe electrolyte and allowing current to flow between the electrodes,wherein depleting or plating one of the electrode materials generates avisible change indicating passage of a duration of time, as described indetail above.

Alternatively, the timing device is an electrochemical-based timingdevice that is actuated with a switch mechanism that closes a circuitbetween electrode elements of a galvanic or an electrolytic cell.Alternatively, the device is fabricated in parts as described above,wherein the parts have contact features, which when brought togetherclose a circuit between the electrode elements of a galvanic or anelectrolytic cell. An actuator switch, in accordance with furtherembodiments of the invention, is in electrical communication with athermosensor, wherein the thermosensor instructs the actuator switch toclose a circuit between electrode elements of a galvanic or anelectrolytic cell within a range of temperatures.

In accordance with yet further embodiments of the invention, a timingdevice and system comprises a photo-sensitive component, element orfilm. For example, a timing device comprises a piece of photographicfilm, which is color film, black and white film or a combinationthereof. The photographic film is formed from a base with a photographicmedium coated or deposited thereon, wherein the photographic film iscapable of being activated to change color or shade and thereby indicatethe passage of a duration of time. The photographic material is anyphotographic medium, but preferably comprises a silver-based materialincluding but not limited to, silver chloride, silver fluoride, silveriodide and/or combinations thereof. In yet other embodiments of theinvention the photographic medium comprises a silver-soap (Ag⁺ cationsin a fatty acid such as stearic acid) often used in thermally-activatedfilms. If the photographic medium is a silver halide, the silver halideis mixed with a binder, such as cellulose or gelatin, to hold the silverhalide material on the base.

The photographic material, in accordance with the embodiments of theinvention, is made to be thermally and/or light sensitive using anynumber of techniques known in the art, including the addition of sulfurand gold and/or a dye, such as an infrared absorbing dye. To activatethe photographic medium a developer is applied to the film. There arenumber of materials that can be used for developing photographicmaterials, such as hydroquinone-based developers. Generally, alldevelopers contain chemicals that assist in the reduction of silverhalide or silver cations to form a darkened or colored image.

In accordance with the embodiments of the invention, a developer isincorporated into the construction of the film and a timing device isthermally activated or is activated by removing a barrier between thephotographic material and the developer. Alternatively, the photographicmaterial and the developer are included an separate parts or regions ofa timing device and are activated by bringing together a part or regionof the film with the photographic material with a part or region of thefilm with the developer.

In accordance with yet further embodiments of the invention, a devicecomprises a film with zones that change color at different rates and,therefore, provide an indication of the passage of a range of times.Each of the zones comprises a photographic material, as explained above,or other chemical and/or electro-chemical materials that can beactivated to change color at different rates. When the zones comprisephotographic materials, the zones are made to have different reactionrates by using photographic materials with different sensitivities toheat, light and/or developer, and/or by varying the thickness ofdiffusion layers deposited over the zones. In accordance with furtherembodiments of the invention, the zones are made to have different ratesof reaction and/or sensitivity to a developer by pre-treating the zonesto a range of different light and/or heat exposures, wherein the zoneswith longer exposures will develop and change color faster than zoneswith shorter exposures.

A system, in accordance with the embodiments of the invention, comprisesa timing film, such as described above, and further comprises anadhesion layer for attaching pieces of film to consumer articles, suchas containers of leftover food. The system also preferably comprises adispenser for conveniently dispensing pieces of film from a stack orroll of the timing film and means, such as a magnet, for attaching thedispenser to a household appliance.

In accordance with a preferred embodiment of the invention, a timingdevice comprises an electrochemical structure, such as described above,that is capable of being activated and configured to generate an audioand/or visual response to indicate a passage of a duration of time afterbeing activated. The timing device also preferably comprises acompensating element such as a varistor, a thermistor and/orcombinations thereof. The compensating element is electrically coupledto the electrochemical structure and regulates the time for the responsewith respect to changes in temperature.

In still further embodiments of the invention, a timing device comprisesan electrochromic structure configured to generate a visual indicationin a prescribed period of time after being activated. The timing devicealso preferably comprises a driver circuit. The driver circuit iselectrically coupled to the electrochromic structure and is configuredto actuate the electrochromic structure in the prescribed period oftime. The driver circuit can include a timing circuit and a batterystructure. Further, the timing circuit can be programmable to generate avisual indication in a range of prescribed periods of time. Also, thetiming device can include zones which are each configured to indicate apassage of a different and predetermined duration of time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-B show a schematic representation of a timing device, inaccordance with the embodiments of the invention.

FIG. 2 shows a schematic representation of a timing device, inaccordance with a preferred embodiment of the invention.

FIGS. 3A-C show systems for assembling timing devices, in accordancewith the method of the present invention.

FIGS. 4A-C show schematic cross sectional views of several timing deviceconfigurations, in accordance with the embodiments of the invention.

FIG. 5 shows a piece of timing film with a plurality of zones forindicating the passage of a range of times, in accordance with theembodiments of the invention.

FIG. 6 is a cross-sectional representation of a section of timing film,in accordance with the embodiments of the invention.

FIGS. 7A-B show schematic cross-sectional views of timing deviceconfigurations with compensator elements, in accordance with theembodiments of the invention.

FIG. 8A shows a reversible reaction sequence for an electrochromicmaterial used in a timing device, in accordance with the embodiments ofthe invention.

FIG. 8B shows a multi-layer construction for an electrochromic device,in accordance with the embodiments of the invention.

FIGS. 9A-B show a timing device with a timer circuit, in accordance withthe embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1A-B, a timing device 100, in accordance with theembodiments of the invention, is a chemical-based timing device, anelectrochemical-based timing device, or a combination thereof. Thetiming device 100 comprises a transparent lens 101, a base 105 and anoptical medium 103 therebetween. When the device 100 is actuated, theoptical medium 103 is changed to a modified medium 103′, therebyaltering the visibility of the base 105 through the lens 101 indicatingthe passage of a duration of time. The lens 101 and base 105 are formedfrom any suitable material, or combination of materials, including, butnot limited to polymers and plastic materials.

Still referring to FIGS. 1A-B, the optical medium 103 comprises anynumber of different chemicals or elements which over the duration oftime alter the visibility of the base 105 through the lens, as explainedin detail below. Preferably, however, the base 105 becomes more visiblethrough the lens 101 when the device 100 has expired (viz. completelyreacted). In order to enhance the visibility of the base 105 through thelens 101, when the device 100 has expired, the base 105 is preferablybrightly colored and/or has indicia printed thereon, such that thebright color and/or the indicia are visible through the lens 101 whenthe device is expired.

Referring now to FIG. 2, in accordance with a preferred embodiment ofthe invention, a timing device 200 comprises a lens 201, a base 211 andan optical medium 204, as described above. The optical medium 204preferably comprises a fluid layer 207. The fluid layer 207 can compriseany number of fluid materials, but preferably comprises a transparentgel material, which is either acidic or basic and which is eitherconductive or insulating, depending on the application at hand. Theoptical medium 204 also preferably comprises an opaque layer 205, alsoreferred to herein as a lens coating layer, which does not imply thatthe opaque layer 205 is necessarily coated directly onto the lens 201.The lens coating 205 is preferably formed from a material which willreact with the fluid layer 207, when the device 200 is activated. As oneexample, the lens coating layer 205 is formed from a hardened gel, suchas gelatin and thiosulfate. Preferably, the fluid layer 207 dissolvesthe lens coating layer 205 when the device 200 is activated, therebyincreasing the visibility of the base 211 therebelow and indicating thepassage of a duration of time.

Still referring to FIG. 2, in further embodiments of the invention, atiming device 200 comprises an activation layer 203. The activationlayer 203 comprises an indicator, such as a pH indicator which reactswith the fluid layer 207, when the fluid layer 207 sufficiently depletesor dissolves the lens coating layer 205. Alternatively, an indicator isincorporated into the lens coating layer 205 and is dissolved or leachedby the fluid layer 207, such that when the concentration of theindicator in the fluid layer 207 becomes sufficiently high, the fluidlayer 207 changes color.

In still further embodiments of the invention, the lens coating layer205 comprises a reactive species that reacts with an indicator in thefluid layer 207. For example, the lens coating layer 205 comprises abase material, such as sodium bicarbonate, which is leached from thelens coating layer 205 or is dissolved into the fluid layer 207 from thelens coating layer 205. The fluid layer 207 comprises a pH indicator andan acidic material and when a sufficient amount of base material isdissolved into the fluid layer 207, then the acidic material isneutralized and the pH indicator changes color, indicating the passageof a duration of time.

In still further embodiments of the invention, a timing device 200comprises a diffusion material 209. When the device 200 is activated,the diffusion material 209 begins to diffuse through the fluid layer207, as indicated by the arrows 215. When the diffusion material 209reaches the lens coating layer 205, the diffusion material 209 reactswith the lens coating layer 205 to provide a color change, dissolve thelens coating layer 205 and react with the indicator layer 203, or anycombination thereof to indicate the passage of a duration of time.

Still referring to FIG. 2, a timing device 200, in accordance with theembodiments of the present invention also comprises an attaching means213 for attaching the timing device 200 to a product or an object (notshown). The attaching means 213 is any suitable attaching means, andpreferably comprises an adhesive layer for sticking the device 200 ontothe product or object.

Now referring to FIG. 3A, a timing system 300, in accordance with apreferred method of the invention, is fabricated in parts 310 and 320. Afirst part 310 of the system 300 comprises a first reactive region 307formed on a suitable base 301. A second part 320 of the system 300comprises a second reactive region 305 formed on a clear lens 303. Oneor both of the parts 310 and 320 comprise adhesive rings 311 and 309,respectively. To actuate the system 300, the parts are brought togethersuch that the first reactive region 307 and the second reactive region305 are in an eclipsed, or overlapping position, and in contact witheach other. The adhesive rings 311 and 309 hold the first part 310 andthe second part 320 together with the reactive regions 305 and 307eclipsed and in contact. While in contact with each other, the firstreactive region 307 and the second reactive region 305 undergo achemical, physical or electrochemical process which alters thevisibility of the base 310 through the lens 303, as described above.Each of the parts 310 and 320 of the system 300, in accordance withfurther embodiments of the invention, comprises a protective covering(not shown), such as a cellophane, which acts to protect the reactiveregions 307 and 305 and is removed before.

Now referring to FIG. 3B, a system 320, in accordance with theembodiments of the invention, is formed by fabricating a plurality offirst reactive regions 322 on a first piece of tape 321 and a pluralityof second reactive regions 324 on a second piece of tape 323. The tapes321 and 323 preferably have perforations 326 and 328 respectivelybetween each of the first reactive regions 322 and the second reactiveregions 324. The tapes 321 and 323 are preferably configured to bedispensed from a roll dispenser (not shown) or any other suitabledispenser. The dispenser can be configured to attach to a householdappliance using a magnet or any other suitable attachment means.

In use, an activated device is formed by removing a first part 327comprising a first reactive region 322 and a second part 329 comprisinga second reaction region 324 from the tapes 321 and 323 through theperforations 326 and 328, respectively. The first part 327 and thesecond part 329 are then combined with the first reactive region 322 andthe second reactive region 324 eclipsed and in contact, as explained indetail above.

Now referring to FIG. 3C, in accordance with alternative embodiments ofthe invention, a system 340 comprises a plurality of first reactiveregions 342 and second reactive regions 344 formed in an alternatingfashion an single piece of tape 343. In use, an activated device isformed from a section 349 comprising a first reactive region 342 and asecond reactive region 344 that is separated from the tape 343 through aperforation 348. The section 349 is then folded over onto itself througha seam 346, such that the first reactive region 342 and the secondreactive region 348 are eclipsed and in contact with each other. WhileFIG. 3C shows the first reactive regions 342 and the second reactiveregions 344 being formed in an alternating fashion an the single pieceof tape 343 such that an active device is formed by folding one of thefirst reactive regions 342 and one of the second reactive regions 344 inan end-to-end fashion, it will be clear to one skilled in the art that asystem can alternatively be formed on single piece of tape with firstreactive regions and second reactive regions formed in rows, such thatan active device is formed by folding one of the first reactive regions342 and one of the second reactive regions 344 in a side-to-sidefashion. It will be appreciated that forming first and second reactiveregions using other configurations is also possible in accordance withthe present invention.

FIG. 4A shows a cross sectional view of a timing device 400, inaccordance with the embodiments of the invention. As describedpreviously, the device 400 comprises a lens 405 and a base 401. Thedevice 400 also comprises an optical medium with one or more fluid lens411 and 411′ and a membrane structure 412 therebetween. The device 400further comprises a lens coating layer 403 and a reactive material 413that is capable of reacting with the lens coating layer 403. To activatethe timing device 400, the membrane structure 412 is ruptured allowingthe reactive material 413 to mix with the fluid layers 411 and 411′ andreact with the lens coating layer 403, thereby indicating the passage ofa duration of time.

Referring now to FIG. 4B, a timing device 420, in accordance withfurther embodiments of the invention, comprises a lens 425, a metal basestructure 421 and one or more ionic fluid media or electrolytes 431 and431′, therebetween. The metal base structure 421 is formed from a firstmetal layer 424 with a first reduction potential and a second metallayer 422 with a second reduction potential that is substantiallydifferent from that of the first metal layer 424. The device 420 alsohas metal lens coating layer 423 with a reduction potential that is alsosubstantially different from that of the first metal layer 424, but canbe the same or nearly the same as the reduction potential of the secondmetal layer 422. To actuate the device the metal lens coating layer 423and the second metal layer 422 are placed in electrical communicationwith each other. The potential difference between the first metal layer424 and the second metal layer 422 will drive a current to flow andcause the metal lens coating layer 423 to become depleted over time, andplate out over the first metal layer, thereby indicating the passage ofa duration of time.

In accordance with the embodiments of the invention, the timing device420 comprises a lens 425 formed from a transparent polymer, such aspolyester, or from a conductive polymer that is coated with a metal lenscoating layer 423, such as aluminum. The timing device 420 furthercomprises a base structure 421 and a second electrode material 422. Thesecond electrode material 422 can be any metal with a reductionpotential that is different from a reduction potential of the firstelectrode material 423. Alternatively, the second electrode material 422can be any metal with a reduction potential that is the same as thereduction potential of the first electrode material 423, when the device420 is being operated as an electrolytic cell (viz. has a batterystructure 421 or other source of electrons to drive the reduction andoxidation process). Between the first electrode material 423 and thebase structure 421 is a colored electrolyte 431. When the timing device420 is activated, the first electrode material 423 is depleted from thetransparent lens 423 and the colored electrolyte 431 becomes visible,thereby indicating the passage of the duration of time.

In yet further embodiments of the invention, a metal screen (not shown)is in contact with one or both of the metal lens coating layer 423 andthe second electrode material 422, to help ensure uniform depletionand/or plating of the electrode materials.

In still further embodiments of the invention, a timing device 420comprises an electrolytes 431 with an indicator that changes when thedevice 420 is activated, such as described above, and theelectrochemical cell generates a sufficient concentration of an ion or apH altering species within the electrolyte.

In accordance with a preferred embodiment of the invention, the firstelectrode material 423 and the second electrode material 422 are inelectrical communication with each other. The timing device 420 furtherincludes a membrane 426 that is positioned between the electrolytes 431and 431′. The membrane 426 is formed from plastic, glass or any othermaterial or combination of materials that are capable of preventing orreducing the migration of ions between the electrolytes 431 and 431′and, thus, prevent or reduce the flow of current between the firstelectrode material 423 and the second electrode material 422. Inoperation, the timing device 420 is actuated by rupturing or breakingthe membrane 426, thereby allowing migration of ions between theelectrolytes 431 and 431′ and allowing current to flow between the firstelectrode material 423 and the second electrode material 422, whereindepletion of the first electrode material 423 generates a visible changethat indicates passage of a duration of time.

In accordance with yet further embodiments of the invention, a timingdevice 440 is coupled to a circuit 450, as shown in FIG. 4C. The device440 comprises a lens 443, a metal base 441, a ionic reactive medium 451and a lens coating layer 445. The ionic reactive medium 451 is capableof depleting or dissolving the lens coating layer 445, either chemicallyor electrochemically as explained previously, when the device 440 isactivated. After the device 440 is activated and the lens coating layer445 is sufficiently depleted or dissolved, the ionic reactive medium 451provides an electrical path to close the circuit 450 between the leads447 and 448. The circuit 450, in accordance with the embodiments of theinvention, comprises a battery 446 and a piezo-electric element 449 thatgenerate an audible signal when the device 440 expires, or is depleted,and the circuit 450 is closed.

In still further embodiments of the invention, a timing device comprisesa galvanic cell or an electrolytic cell, wherein one or moreelectrochemically active materials between a transparent lens and abase, such as metal ions and/or electrodes, are configured to be platedout or depleted and alter the visibility of the base through the lens,thereby indicating the passage of a duration of time. If a timing deviceis an electrochemical-based timing device, an actuator switch mechanismcomprising electrical contacts can be used to actuate the device. Thetiming device, in accordance with still further embodiments of theinvention, is in electrical communication with a thermosensor (notshown), wherein the thermosensor instructs the actuator switch to closea circuit between electrode elements of a galvanic or electrolytic cellwithin a range of temperatures.

In yet further embodiments of the invention, a timing device comprises agalvanic cell or an electrolytic cell with electrodes that areasymmetrically positioned or shaped, such that one of depletion orplating of one of the electrodes occurs and at uneven rate across aviewable portion of a lens. Accordingly, a visual indication of thepassage of time moves across the viewable portion of the leas and thetiming device indicates a range of durations of time. For example, atiming device is configured to deplete an electrode deposited on theviewable portion of the lens from one side of the lens to the other sideof the lens over the range of durations of time. Timing devices inaccordance with further embodiments of the invention are configured toindicate passage of a range of durations of time using electrochemicalzones or photographic zones, such as described below.

Referring to FIG. 5, in accordance with yet farther embodiments of theinvention, a device comprises a film 500 with a plurality of zones(shown as 1-10). The zones can be arranged in any geometric pattern, butare preferably arranged in a linear fashion from a first and 510 to asecond end 520 of the film 500. The zones are configured to change colorat different rates and, therefore, provide an indication of the passageof a range of times. For example, when each of the zones represents onehour, then the film 500 as shown, indicates the passage of approximately7 hours. In approximately one more hour, the next zone will change colorand indicate the passage of approximately 8 hours.

Still referring to FIG. 5, each of the zones, in accordance with theembodiments of the invention, comprises a photographic, chemical and/orelectro-chemical material, as described in detail above. When the zones(shown as 1-10) comprise photographic materials, the zones can be madeto have different rates of reaction by using photographic materials withdifferent sensitivities to heat, light and/or developer and/or byvarying the thickness of diffusion layers deposited over each of thezones, such as described below. In accordance with one embodiment of theinvention, the zones are made to have different rates of reaction and/orsensitivity to a developer by pre-treating the zones to a range ofdifferent light and/or heat exposures, wherein the zones with longerexposures will develop and change color faster than zones with shorterexposures after being activated.

Still referring to FIG. 5, when the zones (shown as 1-10) comprisechemical and/or electro-chemical material(s), as described in detailabove and in accordance with the embodiments of the invention, the zonesare made to have different rates of reactivity and/or sensitivity.Accordingly, each zone has a different expiration time and indicatedpassage of a different amount of time and the zones viewed collectivelyindicate passage of a total time. This embodiment has particularapplications for managing inventories of food items in a householdrefrigerator by indicating how long the food items have been in therefrigerator, regardless of whether or not the food items have spoiledor aged past a freshness date.

FIG. 6 is a cross-sectional representation of a section of timing film600, in accordance with the embodiments of the invention. The section oftiming film 600 is formed by coating or depositing a photographic layer605, which can include silver, silver halide, gelatin, cellulose, fattyacids, developers or combinations thereof onto a base structure 603. Thebase structure 603 is preferably formed from a polymeric material, suchas polyester, and can also include an adhesive layer (not shown) forattaching the section of timing film 600 to a consumer article (also notshown).

Still referring to FIG. 6, the section of film 600, in accordance withthe embodiments of the invention, further comprises a diffusion layer615 comprising a diffusion material and a developer layer 611 comprisinga developer. The diffusion material is any material that will allow thedeveloper in the developer layer 611 to migrate to the photographiclayer 605 causing the photographic layer 605 to change color or darken,thereby indicating the passage of time. Suitable diffusion materialsinclude, but are not limited to, gelatin, cellulose and combinationsthereof.

In accordance with still further embodiments of the invention, thesection of film 600 further comprises a barrier layer 613 that can bepulled out or removed to activate the device and allow the developerlayer 611 to diffuse through the layer 615 and cause the photographiclayer 605 to change color or darken, thereby indicating the passage oftime. Alternatively, the photographic layer 605 and the developer layer611 are formed as separate parts that can be brought together toactivate the device, as explained in detail above with reference toFIGS. 3A-C.

FIG. 7A shows a cross-sectional view of a reactive region 700 of atiming device. The reactive region 700 of the timing device reacts toproduce a visual change and indicate a passage of time, as explainedabove. The timing device can also include a lens and a base (not shown),such as described with reference to FIGS. 1A-B and FIG. 2.

Still referring to FIG. 7A, in accordance with the embodiments of theinvention, the reactive region 700 comprises a first reactive portion701 and a second reactive portion 703. The first reactive portion 701and the second reaction portion 703 are, for example, metals withdifferent reduction potentials that are capable of participating in thegeneration of an electrical potential in a galvanic cell or anelectrolytic cell, as described previously. The reaction region 700 canalso include an electrolyte 705 and electrical connections 711 and 713which allow current to flow between the first reactive portion 701 andthe second reaction portion 703 and generate a visual change to indicatea passage of time, as described above. In accordance with theembodiments of the invention, the reactive region 700 further comprisesa compensating element 707 which is electrically coupled to the firstreactive portion 701 and the second reactive portion 703 to compensatefor changes in electrical potential and rates of reactions that can, andgenerally do, occur as a result of changes in temperature. Thecompensating element 707 can increase or decrease the rate thatelectrons flow through the electrical connections 711 and 713 with achange in temperature. The preferred response to changes in temperaturewill depend on the application at hand. Suitable compensating elementsinclude, but are not limited to, varistors, thermistors (both positivetemperature compensating and negative temperature compensatingthermistors) and/or combinations thereof. A varistor refers to anelement that drops in resistance as the applied voltage across thevaristor is increased. A positive temperature compensating thermistorrefers to an element that drops in resistance as the temperature of thethermistor increases. A negative temperature compensating thermistorrefers to an element that increases in resistance as the temperature ofthe thermistor increases.

Now referring to FIG. 7B, a timing device 720, in accordance theembodiments of the invention, comprises a lens 725, a metal basestructure 721 and an ionic fluid medium or electrolyte 731,therebetween. The metal base structure 721 is formed from a first metallayer 724 with a first reduction potential and a second metal layer 722with a second reduction potential that is substantially different fromthat of the first metal layer 724. The device 720 also has metal lenscoating layer 723 with a reduction potential that is also substantiallydifferent from that of the first metal layer 724, but can be the same ornearly the same as the reduction potential of the second metal layer722. To actuate the timing device 720 the metal lens coating layer 723and the second metal layer 722 are placed in electrical communicationwith each other through connectors 731 and 733. The potential differencebetween the first metal layer 724 and the second metal layer 722 willdrive a current to flow and cause the metal lens coating layer 723 tobecome depleted over time, and plate out over the first metal layer 724,thereby indicating the passage of a duration of time. Between theelectrical connections 731 and 733 there is a compensating element 707,such as described above, that changes resistance in response to changesin applied potential, current flow, temperature or a combinationthereof, thus making the timing device either more stable to the changesin temperature or more sensitive to the changes in temperature.

In accordance with yet further embodiments of the invention, a timingdevice utilizes an electrochromic material. An electrochromic materialrefers to a material that changes color when the composition of thematerial is changed by use of an electrochemical cell or other voltagesource. Electrochromic materials often exhibit reversible color changesand can be switched between two or more color states by reversing thepolarity of an applied potential of a layer comprising the material thatis in contact with an ion or metal ion source, as described in detailbelow. A number of materials exhibit electrochromism, including but notlimited to, tungsten oxide, molybdenum oxide, titanium oxide, niobiumoxide, iridium, oxide and rhodium oxide, to name a few.

FIG. 8A shows an exemplary reaction for electrochromic tungsten oxide803, which is transparent. To change the color of the tungsten oxide803, electrons 804 are provided from a cathodic site of the device whichreduces ions or metal ions (M+) from an ion source 802. The reduced ionsor atoms then combine with the tungsten oxide 803 to form ametal-tungsten oxide complex or structure 805 which is blue. The processcan be reversed by oxidizing the metal-tungsten oxide complex orstructure 805 at an anodic site of the device.

FIG. 8B shows a schematic representation of a multi-layeredelectrochromic device 800 in accordance with the embodiments of theinvention. The electrochromic device 800 comprises containment layers821 and 833, at least one of which is transparent so that color changesin an electrochromic layer 825 can be observed. The device 800 also haselectrode layers 823 and 829, the electrochromic layer 825 and a metalion source layer 827 therebetween. The electrochromic layer 825comprises one or more electrochromic materials and the metal ion sourcelayer 827 comprises metal ions 822, such as those described above withrespect to FIG. 8A. In operation, an electrical potential is appliedacross the electrode layers 823 and 829 and electrons 824 and 826 flowinto the electrochromic layer 825 from the electrode layer 823. Metalions 822 migrate from the metal ion source layer 827 into theelectrochromic layer 825 where the metal ions are reduced by theelectrons 824 and combine with an electrochromic material to produce acolor change within the electrochromic layer 825. The electricalpotential can be applied across the electrode layers 823 and 829 using abattery 832 that is electrically coupled to the electrode layer 823 and829 through electrical connections 828 and 830, respectively and one ormore conductive layers 831. As described previously, the process can bereversed by reversing the polarity of the battery 832.

Now referring to FIG. 9A, a timing device 900, in accordance with theembodiments of the present invention, comprises a layered electrochromicstructure 916, which can include transparent constrainment layers 901and 907 with an electrochromic layer 905 therebetween, similar to thatdescribed with reference to FIG. 8B. The timing device 900 can alsoinclude a base structure 903 that is viewable through the layeredelectrochromic structure 916 when the electrochromic layer 905 is in atransparent color state. The device 900 also preferably includes adriver circuit 910 that includes a voltage source 926 (FIG. 9B) that iselectrically coupled to the electrochromic layer 905 through electricalconnections 911 and 913. When an electrical potential is applied acrossthe electrochromic layer 905, the electrochromic structure 916 switchesfrom transparent to opaque and/or colored or switches for opaque and/orcolored to transparent depending on the polarity of the electricalpotential that is applied.

Now referring to FIG. 9B, the driver circuit 910, in accordance with theembodiments of the invention, comprises a timing circuit 920, such as adigital timing circuit and a battery structure 926 for providing theelectrical potential. The battery structure 926 comprises any suitableelements capable of generating an electrical potential sufficient tochange the color state of the electrochromic layer 905 (FIG. 9A).Suitable battery elements include, but are not limited to, a firstelectrode structure 921, a second electrode structure 923 and anelectrolyte structure 922. In operation, the timing circuit 920 can actas a switch that maintains an open circuit between the battery structure926 and the electrochromic layer 905 (FIG. 9A) for a prescribed periodof time and then closes the circuit between the battery structure 926and the electrochromic layer 905 after the prescribed period of time,causing a color change in the layered electrochromic structure 916 (FIG.9A).

In accordance with yet further embodiments the invention, the drivercircuit 910 is programmable and can be programmed to switch or changethe color state of the layered electrochromic structure 916 in a rangeof prescribed times that are selectable by the user and/or manufacturer.In still further embodiments of the invention, the layeredelectrochromic structure 916 is divided into zones, wherein the zonesare activated in a range of prescribed times and the zones individuallyor collectively change color to indicate the passage of time or thepassage of a range of times, such as previously described with referenceto FIG. 5.

In accordance with still further embodiments of the invention, a timingdevice comprises an electrochemical cell configuration, such asdescribed with respect to FIGS. 4B-C and 7B, wherein the timing devicecomprises a plurality of sub cells or zones that individually orcollectively indicate the passage of time or the passage of a range oftimes, such as previously described with reference to FIG. 5. Forexample, a timing device is configured with a plurality of sub cells orzones that each includes a first set of electrodes formed from a firstelectrode material. The first electrodes are electrically isolated fromeach other and are in electrical communication with a second electrodeor second set of electrodes formed from a second electrode materialthrough resistors having a range of different resistivities.

The current invention has applications for marking when any number ofdifferent events need to take place and/or for timing the duration ofany number of different events. For example, the timing device of thepresent invention has applications for indicating when perishablematerials have expired and need to be thrown out, indicating the age ofinventory and managing when the inventory needs to be rotated, trackinga deadline and a host of other time and/or temperature dependent events.One advantage of the present invention is that the timing device can befabricated in two or more reactive parts, wherein the device is notactivated, or sensitive to the environment (such as temperature), untilthe parts are coupled together, as explained in detail above.Accordingly, the shelf life of the timing device prior to use isenhanced and the sensitivity of the device to environmental conditionsprior to use is reduced.

The present invention has been described in terms of specificembodiments incorporating details to facilitate the understanding of theprinciples of construction and operation of the invention. As such,references, herein, to specific embodiments and details thereof are notintended to limit the scope of the claims appended hereto. It will beapparent to those skilled in the art that modifications can be made inthe embodiment chosen for illustration without departing from the spiritand scope of the invention.

What is claimed is:
 1. A timing device for monitoring one or more timeperiods comprising: a. a first reactive chemical cell indicating a firsttime period; b. a second chemical cell independent from the firstreactive chemical cell and indicating a second time period, wherein thefirst reactive chemical cell and the second reactive chemical cellcollectively indicate a third total elapsed time period; and c. anactivation mechanism for activating the timing device, wherein theactivation mechanism activates the first reactive chemical cell and thesecond reactive chemical cell at the same time.
 2. The timing device ofclaim 1, wherein the first reactive chemical cell and the secondreactive chemical cell indicate a same time amount.
 3. The timing deviceof claim 1, wherein the first reactive chemical cell and the secondreactive chemical cell are arranged in a linear fashion.
 4. The timingdevice of claim 1 comprising a mechanism for attaching the device to anadditional article.
 5. The timing device of claim 4, wherein theadditional article is a time sensitive item.
 6. The device of claim 1,wherein a first part of the timing device and a second part of thetiming device are brought into contact in order to activate the device.7. The device of claim 6, wherein the first part and the second part areseparated by a removable structure.
 8. The timing system of claim 1,wherein the first reactive chemical cell and the second reactivechemical cell indicate a time period by changing color.
 9. A timingsystem comprising: a. a timing scale comprising: i. a first reactivechemical cell indicating a first time period; ii. a second reactive zoneindependent from the first reactive chemical cell and for indicating asecond time period, wherein the first reactive chemical cell and thesecond reactive chemical cell collectively indicate a third totalelapsed time period; b. a mechanism for attaching the system to anadditional article; and c. an activation mechanism for activating thesystem.
 10. The timing system of claim 9, wherein the timing scaleindicates an amount of elapsed time.
 11. The timing system of claim 9,wherein the third time period indicates a total amount of elapsed time.12. The timing system of claim 9, wherein the first reactive chemicalcell and the second reactive chemical cell are arranged in a linearfashion.
 13. The timing system of claim 9, wherein the additionalarticle is a time sensitive item.
 14. A method of monitoring a period oftime: a. attaching a timing device to an item; and b. activating thetiming device, wherein after activation, a first reactive chemical cellof the timing device indicates a first time period, a second reactivechemical cell of the timing device independent from the first reactivechemical cell indicates a second time period, and wherein the firstreactive chemical cell and the second reactive chemical cellcollectively indicate a third total elapsed time period.
 15. The methodof claim 14, wherein a timing scale indicates an amount of elapsed time.16. The method of claim 14, wherein the third time period indicates atotal amount of elapsed time.
 17. The method of claim 14, wherein thefirst reactive chemical cell and the second reactive chemical cell arearranged in a linear fashion.
 18. The method of claim 14, wherein theitem is a time sensitive item.
 19. The method of claim 18, wherein thetime sensitive item is a perishable item.
 20. The timing system of claim14, wherein the time sensitive item is a perishable item.